SQL Server 2008 R2 - Free Book from Microsoft
If you are a sql server developer and wanted to have some free ebook on sql server 2008.
Here is the link I found while looking for the same. There is a free ebook download available on microsoft site for "SQL Server 2008 R2" edition.
This online book is the primary documentation for SQL Server.
Books Online includes the following types of information:
Setup and upgrade instructions.
Information about new features and backward compatibility.
Conceptual descriptions of the technologies and features in SQL Server.
Procedural topics describing how to use the various features in SQL Server.
Tutorials that guide you through common tasks.